Organic light-emitting diode and manufacturing method thereof

ABSTRACT

An organic light-emitting diode and a manufacturing method thereof are provided. The organic light-emitting diode includes: a substrate ( 10 ) and a first light extraction layer ( 20 ), a first electrode layer ( 30 ), a light-emitting layer ( 40 ), a second electrode layer ( 50 ) and an encapsulation layer ( 70 ) that are sequentially disposed on the substrate, wherein the organic light-emitting diode further includes a second light extraction layer ( 60 ), and the second light extraction layer ( 60 ) is disposed adjacent to the encapsulation layer ( 70 ); the light-emitting layer ( 40 ) is an organic light-emitting layer and the first electrode layer ( 30 ) is an anode layer or a cathode layer and correspondingly the second electrode layer ( 50 ) is a cathode layer or an anode layer.

TECHNICAL FIELD

Embodiments of the present disclosure relate to an organiclight-emitting diode and a manufacturing method thereof.

BACKGROUND

An organic light-emitting diode (OLED) relates to the luminescencetechnology of an organic semiconductor material under the effect ofelectric field. The organic light-emitting diode has the advantages ofactive luminescence, all-solid-state, low driving voltage, highefficiency, short response, wide visual angle, simple manufacturetechnology and can realize a large area and flexible display, etc, so ithas an extensive application prospect in the aspects of flat-paneldisplaying and lighting.

The performance of a single-color OLED is gradually mature. A WOLED(white organic light-emitting diodes) as a new type of solid-state lightsource has shown a perfect application prospect in the aspects oflighting and flat-panel displaying back-light, etc, and it has attractedmore and more attentions of the people. At present, in terms of luminousefficiency, the commercial OLED has surpassed the incandescent (˜10lm/W). However, compared with the requirement that is at least 100 lm/Wof the next generation of solid-state lighting (SSL), the luminousefficiency of the commercial OLED is still not enough.

SUMMARY

The present disclosure provides an OLED device with multiple lightextraction layers and a manufacturing method of the OLED device. Theloss of the luminous efficiency caused by the total reflection of theinterior light in the device is reduced and the luminous efficiency ofthe organic light-emitting display device is improved effectively.

Embodiments of the present invention provide an organic light-emittingdiode, which includes: a substrate and a first light extraction layer, afirst electrode layer, a light-emitting layer, a second electrode layerand an encapsulation layer that are sequentially disposed on thesubstrate, wherein the organic light-emitting diode further comprises asecond light extraction layer, and the second light extraction layer isdisposed adjacent to the encapsulation layer; the light-emitting layeris an organic light-emitting layer and the first electrode layer is ananode layer or a cathode layer and correspondingly the second electrodelayer is a cathode layer or an anode layer.

For example, the organic light-emitting diode further includes: a holeinjection layer and a hole transport layer that are sequentiallydisposed between the anode layer and the light-emitting layer; and/or anelectron injection layer and an electron transport layer that aresequentially disposed between the cathode layer and the light-emittinglayer.

For example, the substrate is an array substrate (TFT) and the anodelayer is electrically connected with the switch element of the arraysubstrate.

For example, the first light extraction layer is made of nano-glasspowder.

For example, the nano-glass powder includes ZnO, BaO and B₂O₃.

For example, in the nano glass powder, the mass ratio of ZnO, BaO andB₂O₃ is 1 to 2:1 to 5:1 to 2.

For example, the thickness of the first light extraction layer is 10 nmto 50 nm.

For example, the second light extraction layer is made of a resinmaterial.

For example, the resin material is a light-cured resin or a heat-curedresin.

For example, the surface of the second light extraction layer has aregular texture structure.

Another embodiment of the present invention further provides amanufacturing method of the organic light-emitting diode, comprising:providing a substrate; forming a first light extraction layer, a firstelectrode layer, a light-emitting layer, a second electrode layer and anencapsulation layer sequentially on the substrate, wherein the methodfurther includes disposing a second light extraction layer, and thesecond light extraction layer is disposed adjacent to the encapsulationlayer (i.e. the second light extraction layer can be between theencapsulation layer and the second electrode layer, and also can be onthe outside surface of encapsulation layer), the light-emitting layer isan organic light-emitting layer and the first electrode layer is ananode layer or a cathode layer and correspondingly the second electrodelayer is a cathode layer or an anode layer.

For example, the method can also include: forming a hole injection layerand a hole transport layer between the anode layer and thelight-emitting layer sequentially; and/or forming an electron injectionlayer and an electron transport layer between the cathode layer and thelight-emitting layer sequentially.

In the above-mentioned methods, for example, forming the first lightextraction layer comprises: coating a light extraction layer material onthe substrate; pre-baking to remove the solvent of the coated lightextraction layer material; sintering in nitrogen gas to remove theorganic material.

In the above-mentioned methods, for example, the light extraction layerincludes nano-glass powder.

In the above-mentioned methods, for example, the nano-glass powderincludes ZnO, BaO and B₂O₃.

In the above-mentioned methods, for example, forming the second lightextraction layer comprises: coating a resin material on theencapsulation layer by a printing process; solidifying the resinmaterial through a heating process or an UV light curing process.

In the above-mentioned methods, for example, the resin material is alight-cured resin or a heat-cured resin.

For example, the method can also include forming a regular texturestructure on the surface of the second light extraction layer.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly illustrate the technical solution of the embodimentsof the invention, the drawings of the embodiments will be brieflydescribed in the following; it is obvious that the described drawingsare only related to some embodiments of the invention and thus are notlimitative of the invention.

FIG. 1 is a schematic structure diagram of an OLED device;

FIG. 2 is a schematic structure diagram of an OLED device in anembodiment of the present disclosure;

FIG. 3 is a schematic structure diagram of an OLED device in anotherembodiment of the present disclosure;

FIG. 4 is the surface morphology of the first light extraction layer ofan embodiment of the present disclosure;

FIG. 5 is the luminescent spectrum comparison chart of the OLED in anembodiment of the present disclosure and the OLED in a contrastingexample under the same conditions.

DETAILED DESCRIPTION

In order to make objects, technical details and advantages of theembodiments of the disclosure apparent, the technical solutions of theembodiment will be described in a clearly and fully understandable wayin connection with the drawings related to the embodiments of thedisclosure. It is obvious that the described embodiments are just a partbut not all of the embodiments of the disclosure. Based on the describedembodiments herein, those skilled in the art can obtain otherembodiment(s), without any inventive work, which should be within thescope of the disclosure.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present invention belongs. The terms“first,” “second,” etc., which are used in the description and theclaims of the present application for invention, are not intended toindicate any sequence, amount or importance, but distinguish variouscomponents. Also, the terms such as “a,” “an,” etc., are not intended tolimit the amount, but indicate the existence of at least one. Thephrases “connect”, “connected”, etc., are not intended to define aphysical connection or mechanical connection, but may include anelectrical connection, directly or indirectly.

Unless otherwise defined, names and chemical formulas express the samemeaning in the text, for example zinc oxide and ZnO, barium oxide andBaO, boron trioxide and B₂O₃, etc.

The luminous efficacy of the OLED device is equal to the product of thefollowing three factors: luminous efficacy radiation (LER), electricalefficiency (EE) and external quantum efficiency (EQE). The externalquantum efficiency is equal to the product of the internal quantumefficiency (IQE) and the light extraction efficiency (LEE). In the abovefactors, in general, the greatest room for improvement is the lightextraction efficiency (LEE). Typically, the refractive indexes of theorganic layer and the glass substrate are about 1.8 and about 1.5respectively and the refractive index of the air is about 1.0. Accordingto the Fresnel's law, because of the existing of the total internalreflection of the light in interfaces of different media, only about 20%light can be emitted from the OLED device.

Many methods have been proposed to improve the light extractionefficiency LEE by decreasing the total internal reflection of the lightin interfaces, for example, microstructures in micron scale or opticalgratings in nanoscale are prepared on the glass substrate, or scatteringlayers or diffraction optical gratings are prepared on the organiclayer. But these methods focus on reducing the light travel loss on oneinterface of the device, although at last the LEE can be improved tosome extent, the effect is limited.

The inventors of the present invention found in the study, if the lighttravel loss on each interface of the device is reduced as much aspossible, the luminous efficiency of the OLED device can be furtherimproved significantly.

FIG. 1 is a structure of a white OLED device, and the structurecomprises: an anode layer, a first hole injection layer (HIL1), a firsthole transport layer (HTL1), a blue light-emitting layer (EBML), a firstelectron transport layer (ETL1), a charge generation layer (CGL), asecond hole transport layer (HTL2), a yellow light-emitting layer(EYML), an electron transport layer (ETL), a cathode layer and anencapsulated layer (CPL) that are sequentially disposed on thesubstrate.

OLED device can have types of top emission, bottom emission ordouble-side emission, etc. If it is disposed as a top emission type, areflector layer would be disposed on a side of the substrate; If it isdisposed as a bottom emission type, a reflector layer would be disposedon the outside of the encapsulated layer. The inventors found in thestudy, whether the top emission type or the bottom emission type, ifonly pay attention to the loss of the emitted light on the ejectinginterface of the OLED would not improve the efficiency of the OLEDdevice effectively. For example, for the top emission, if only payattention to the loss of the interface between the CPL and the air, orfor the bottom emission, if only pay attention to the loss of theinterface between the substrate and the air, the efficiency of the OLEDdevice would not be improved effectively.

The inventors of the present invention found, in the OLED the lighttravel loss did not only happen on one interface, the light travel losshappened on different interfaces of the device in the internal was alsovery big. So the light extraction layers are disposed on the twointerfaces at the same time in the embodiment of the present inventionto further improve the luminous efficiency of the OLED device.

Embodiment of the present invention provides an organic light-emittingdiode, which includes: a substrate and a first light extraction layer, afirst electrode layer, a light-emitting layer, a second electrode layerand an encapsulation layer that are sequentially disposed on thesubstrate. The organic light-emitting diode further comprises a secondlight extraction layer, and the second light extraction layer isdisposed adjacent to the encapsulation layer; the light-emitting layeris an organic light-emitting layer and the first electrode layer is ananode layer or a cathode layer and correspondingly the second electrodelayer is a cathode layer or an anode layer.

As shown in FIG. 2, embodiment of the present invention provides anorganic light-emitting diode, which includes: a substrate 10 and a firstlight extraction layer 20, an anode layer 30, a light-emitting layer 40,a cathode layer 50, a second light extraction layer 60 and anencapsulation layer 70 that are sequentially disposed on the substratefrom the bottom up. In another embodiment, the position relationsbetween the second light extraction layer 60 and the encapsulation layer70 can be switched. In another embodiment, the positions of the anodelayer 30 and the cathode layer 50 can be switched.

In the embodiment of the present invention, the substrate 10 as astructural support of the organic functional layer has a certain abilityto prevent water vapor and oxygen permeating and has a better surfacesmoothness. The substrate 10 for example can be a glass substrate, aquartz substrate, a plastic substrate, etc. A buffer layer and otherlayer structures can be disposed on the substrate 10, or a drivingcircuit has been prepared in advance, for example an active matrixdriving circuit includes gate lines, data lines, power lines, thin filmtransistors which used as switch elements and driving components,capacitors or a passive matrix driving circuit includes gate lines, datalines and switch elements and so on. When an active matrix drivingcircuit is disposed on the substrate, it can also be called an arraysubstrate or a TFT substrate, etc.

The anode layer 30 as a positive voltage connection layer of the organiclight-emitting diode has good conductivity and visible lighttransparency and a high work function. For example, the anode layer 30is usually made of an inorganic metal oxide (such as indium tin oxideITO, zinc oxide ZnO, etc.) or an organic conducting polymer (such asPEDOT: PSS, PANI, etc.) or a metal material with a high work function(such as gold, copper, silver, platinum and so on). For example, theanode layer 30 can be an ITO thin film, and its square resistance forexample is 25 Ω/□.

The cathode layer 50 as a negative voltage connection layer of the OLEDhas good conductivity and a low work function. The cathode layer 50 isusually made of a metal with a low work function such as lithium,magnesium, calcium, strontium, aluminum, indium, etc or the alloy of themetal material with a low work function and copper, gold, silver and soon.

The encapsulation layer 70 for example can be a glass layer, and it canalso be a composite encapsulation layer that includes various inorganicinsulator layers or a composite encapsulation layer that includesinorganic insulator layers and organic insulator layers.

For example, according to the different organic light-emitting materialsthe light-emitting layer 40 used, the light-emitting layer 40 can emitred light, green light, blue light, yellow light, white light and so on.The embodiment of the present disclosure is not limited to the color ofthe light emitted by the light-emitting layer. Besides, according to theneed, organic light-emitting materials of the organic light-emittinglayer in the embodiments of the disclosure include fluorescentlight-emitting materials or phosphorescence light-emitting materials,and at present usually use an adopt-mixed system, that is the usablelight-emitting materials are obtained by adding the doping materials tothe main light-emitting materials. For example, the metal complexmaterials, the derivatives of anthracene, aromatic diamine compounds,triphenylamine compounds, aromatic triamine compounds, biphenyl diaminederivatives, or triarylamines polymers, etc can be used as the mainlight-emitting materials; More specifically, for example, double(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1′-biphenyl-4-hydroxy aluminium(Balq),9,10-di(2-naphthyl) anthracene (ADN), TAZ, 4,4′-di(9-carbazole)biphenyl (CBP), MCP, 4,4′,4′-tri(9-carbazole base) triphenylamine (TCTA)or N,N-double (alpha-naphthyl-phenyl)-4,4-biphenyl diamine (NPB), etc.The fluorescent light-emitting materials or the mixed materials, forexample, include coumarin dyes (coumarin 6, C-545-t), quinacridone(DMQA), or 4-(dinitrilemethylene)-2-methyl-6-(4-dimethylamino-styrene)-4H-pyran (DCM) series,etc. The phosphorescence light-emitting materials or the dopedmaterials, for example, include the metal complex luminescence materialsbased on the Ir, Pt, Ru, Cu metal, etc. For example: FIrpic, Fir6,FirN4, FIrtaz, Ir(ppy)₃, Ir(ppy)₂(acac), PtOEP, (btp)₂Iracac,Ir(piq)₂(acac) or (MDQ)₂Iracac and so on. Besides, the light-emittingmaterials can also include the double main body and doping material.

The first light extraction layer 20 disposed between the anode layer 30and the the substrate 10 is made of nano-glass powder. The maincomponents of the nano-glass powder, for example, can be ZnO, BaO andB₂O₃. The proportion of the three components is adjusted according tothe refractive index of the final combination, the refractive index ofthe zinc oxide is 2.008 to 2.029; the refractive index of the bariumoxide is 1.485 to 1.64; the refractive index of the boron trioxide is1.98. The proportion of the three components can be adjusted to make therefractive index of the final combination between the anode layer (therefractive index is about 1.8) and the substrate (the refractive indexof the substrate is about 1.5) which are adjacent to it. For example,the mass ratio of ZnO, BaO and B₂O₃ is 1 to 2:1 to 5:1 to 2. Thethickness of the first light extraction layer 20 can not be particularlylimited, and it can refer to the thickness of the adjacent layer. Forexample, the thickness of the first light extraction layer 20 is 10 nmto 50 nm, for example, 20 nm to 30 nm. Because the refractive index ofthe first light extraction layer 20 is between the anode layer and thesubstrate, the total reflection originally occurred between the anodelayer 20 and the substrate 10 is greatly reduced.

The second light extraction layer 60 is commonly made of a resinmaterial, the resin materials, for example can be a light-cured resin ora heat-cured resin. The examples of the resin materials can be listedinclude polycarbonate (PC, the refractive index n=1.59), polyethyleneterephthalate (PET, the refractive index n=1.65), polyethylenenaphthalate (PEN, the refractive index n=1.78), etc. For example, aregular texture structure can be disposed on the surface of the secondlight extraction layer 60. An example of the surface morphology of theregular texture structure is shown in FIG. 4.

Because the refractive index of the second light extraction layer 60 isnear the refractive index of the encapsulation layer 70 or the cathodelayer 50 which are adjacent to it, the light emitted from the organiclight-emitting layer can be transmitted to the second light extractionlayer 60 and has no total reflection loss. Because of the existing ofthe regular texture structure which is disposed on the surface of thesecond light extraction layer 60, the total reflection is also greatlyreduced when the light emits from the optically denser medium (forexample an electrode, an encapsulation layer and an organic functionallayer, etc) to the air, and then the loss of the emitting light is alsoreduced. Meanwhile, because the first light extraction layer 20 and thesecond light extraction layer 60 are existed at the same time, both thetotal reflection occurred on the surface of the encapsulation layer andthe total reflection occurred between the anode and the substrate aregreatly reduced, the loss of the light is significantly reduced when theemitting light travels in the device and at last the luminous efficiencyof the OLED device is significantly improved.

As shown in FIG. 3, another embodiment of the present disclosureprovides a white OLED device. The device can emit white light bycombining the light-emitting layers emitting light with differentcolors. The structure of the white OLED device includes: a substrate anda first light extraction layer, an anode layer, a first hole injectionlayer (HIL1), a first hole transport layer (HTL1), a blue light-emittinglayer (EBML), a first electron transport layer (ETL1), a chargegeneration layer (CGL), a second hole transport layer (HTL2), a yellowlight-emitting layer (EYML), an electron transport layer (ETL), acathode layer and an encapsulated layer (CPL) and a second lightextraction layer that are sequentially disposed on the substrate.However, the relative relation of the second light extraction layer andthe encapsulated layer is not limited to the specific case showed in theFIG. 3. For example, the second light extraction layer can be disposedbetween the encapsulated layer and the cathode layer. Meanwhile, in anembodiment of the present disclosure, the combination of thelight-emitting layer with different colors is not limited to thecombination of the embodiment showed in FIG. 3 and the combination canbe the other suitable combinations. The top and bottom relativepositions of the blue light-emitting layer and the yellow light-emittinglayer can be exchanged, and the positions of the function layerscorresponding to them are also adjusted according to them.

In the case of external electric field is applied, the charge generationlayer (CGL) can produce electrons and holes. The produced electrons andholes combine with the holes injected from anode and the electronsinjected from cathode respectively on the light-emitting layer to emitlight. The OLED device has realized high brightness, high efficiency,long life and so on at low current density, and the possibility that thelaminating device is widely used in the fields of solid-state lightingand panel display. In the white OLED device, the CGL layer can plays therole of adjusting the balance of the carrier. The examples of thestructure of the charge generation layer include: Mg:Alq₃(BPhen,TPBi/MoO₃, Cs₂CO₃:Alq₃(BPhen, TPBi/MoO₃, CsN₃:Alq₃/MoO₃, Mg(Cs₂CO₃):TPBi/HAT-CN, Cs₂CO₃/Al/MoO₃ and so on.

The hole injection layer, for example can be made of triphenylaminecompounds or organic layers with p-type doped or polymers, for example:tri[4-(5-phenyl-2-thiophene) phenyl] amine, 4,4′,4″-tri[2-naphthyl(phenyl) amino] triphenylamine (2-TNATA) or 4,4′,4″-tri(3-methyl phenylaniline) triphenylamine (m-MTDATA), copper phthalocyanine (CuPc), Pedot:Pss, TPD, or F4TCNQ.

The hole transport layer, for example can be made of aromatic diaminecompounds, triphenylamine compounds, aromatic triamine compounds,biphenyl diamine derivatives, triarylamine polymers and carbazolepolymers. Such as the NPB, TPD, TCTA and polyethylene carbazole or itsmonomer.

The electron transport layer, for example can be made of phenanthrolinederivatives, oxazole derivatives, thiazole derivatives, imidazolederivatives, metal complexes and anthracene derivatives. The specificexamples include: 8-hydroxyquinoline aluminum (Alq₃), 8-hydroxyquinolinelithium (Liq), 8-hydroxyquinoline gallium, double[2-(2-hydroxylphenyl-1)-pyridinel] beryllium,2-(4-diphenyl)-5-(4-tert-butylbenzene)-1,3,4 oxadiazoles(PBD),1,3,5-tri(N-phenyl-2-benzimidazole-2) benzene (TPBI), BCP, Bphen, etc.

The electron injection layer, for example can be made of alkali metaloxides, alkali metal fluorides, etc. The alkali metal oxides includelithium oxide (Li₂O), lithium boron oxide (LiBO), potassium silicate(K₂SiO₃), cesium carbonate (Cs₂CO₃), etc. The alkali metal fluoridesinclude lithium fluoride (LiF) and sodium fluoride (NaF), etc.

An embodiment of the present disclosure further provides a displayapparatus, and the display apparatus includes the above-mentionedorganic light-emitting diode which is used to form the sub-pixel havingat least one color according to at least one embodiment of the presentdisclosure, for example, a red, a green and a blue (RGB) sub-pixel.These sub-pixels constitute a pixel array. For example, the displayapparatus can be: a mobile phone, a tablet computer, a television, amonitor, a notebook computer, a digital picture frame, a navigationsystem, a watch and any other products or components having a displayfunction.

Accordingly, another embodiment of the present disclosure furtherprovides a manufacturing method of the organic light-emitting diode, andthe method comprises: providing a substrate; disposing a first lightextraction layer, a first electrode layer, a light-emitting layer, asecond electrode layer and an encapsulation layer sequentially on thesubstrate. The method also includes further disposing a second lightextraction layer, and the second light extraction layer is disposedadjacent to the encapsulation layer; the light-emitting layer is anorganic light-emitting layer and the first electrode layer is an anodelayer or a cathode layer and correspondingly the second electrode layeris a cathode layer or an anode layer.

Oxygen plasma or argon plasma can be used to preprocess the anode layerpretreatment to improve the cleanliness and surface roughness of the ITOfilm, to improve the surface properties and the work function values ofthe ITO thin film.

For example, in an example, the substrate is cleaned in the cleaningagent, the ethanol solution, the acetone solution, and the deionizedwater successively, and then the substrate is dried by dry nitrogen.

For example, the method can further include: forming a hole injectionlayer and a hole transport layer between the anode layer and thelight-emitting layer sequentially; and/or forming an electron injectionlayer and an electron transport layer between the cathode layer and thelight-emitting layer sequentially.

In an example of the embodiment, forming the first light extractionlayer for example can comprise: coating a light extraction layermaterial on the substrate, in addition to the nano glass powder, forexample, the light extraction layer material further including acellulose resin, an adhesion promoter and a solvent; pre-baking toremove the solvent of the coated light extraction layer material, thetemperature range of pre-baking, for example, being 70° C. to 120° C.and the time of pre-baking, for example, being 20 min to 30 min;sintering in nitrogen gas to remove the organic material, thetemperature of sintering, for example, being 370° C. to 480° C. and thetime of sintering, for example, being 40 min to 90 min.

In the method, for example, the light extraction layer includesnano-glass powder.

In the method, for example, the nano-glass powder includes ZnO, BaO andB₂O₃.

In another example of the embodiment of the present disclosure, formingthe second light extraction layer comprises: coating a resin material onthe encapsulation layer by a printing process, for example, thecomponent of the resin includes styrene acrylic resin, solvent andadditive; solidifying the resin material by a heating technology or anUV light curing technology, the technological condition of solidifying,for example, is treating in the temperature of 60° C. to 90° C. for60˜120 s.

In the method, for example, the resin material is a light-cured resin ora heat-cured resin.

For example, the method further comprises forming a regular texturestructure on the surface of the second light extraction layer and thetexture structure is shown in FIG. 4. The texture structure for example,can be formed in the methods of stamping, etching, lithography and soon.

In the organic light-emitting diode of the embodiment of the presentdisclosure, the deposition rate and the thickness of each organicfunctional layer, for example, can be monitored by the film thicknessgauge disposed near the substrate. Besides, each of the organicfunctional layers can be prepared in the methods of evaporation or metalorganic chemical vapor deposition (MOCVD). After that, the preparedorganic light-emitting diode is transformed to the hand box toencapsulation, the hand box has an atmosphere of inert gas, for example,in the present embodiment, and the hand box has an atmosphere ofnitrogen gas. After that, the photoelectric properties of the preparedorganic light-emitting diode can be tested.

In order to illustrate the technical effects of the embodiment of thepresent disclosure, an OLED device having two light extraction layers isprepared in another embodiment of the present disclosure, and itsstructure is shown in FIG. 3. As a comparative example, an OLED devicehaving no light extraction layer is prepared according to the samemethod, and its structure is shown in FIG. 1; an OLED device only havinga second light extraction layer is prepared (its structure can refer toFIG. 3, in addition to the first light extraction layer is omitted, theremaining is unchanged). In addition to the above differences, the othersettings (such as the materials of each layer, the thickness of eachlayer, the preparation method of each layer, etc.) of the structure ofthe three kinds of OLED devices are the same. The light-emitting spectraof the three kinds of OLED devices are tested under the same testconditions, and the results are shown in FIG. 5. It can be seen fromFIG. 5 that the OLED device having no light extraction layer shows thelowest luminous efficiency. The luminous efficiency of the OLED devicedisposed with a second light extraction layer is improved in a certainextent, wherein the blue area is improved more obvious, yellow area isnot as obvious as the blue area and the red area is not obvious. Theluminous efficiency of the OLED device disposed with a first lightextraction layer and a second light extraction layer at the same time isfurther improved, and all the luminous efficiency in the blue area, theyellow area and the red area are obviously improved, and the promotionin blue area is the most significant. It can be seen, compared with theexisting OLED, the luminous efficiency of the OLED provided by theembodiment of the present disclosure which has a first light extractionlayer and a second light extraction layer at the same time issignificantly improved.

What are described above is related to the illustrative embodiments ofthe disclosure only and not limitative to the scope of the disclosure;the scopes of the disclosure are defined by the accompanying claims.

The present application claims the priority of the Chinese PatentApplication No.201510218730.3 filed on Apr. 30, 2015, the entirety ofwhich is incorporated herein by reference as a part of the presentapplication.

1. An organic light-emitting diode, comprising: a substrate and a firstlight extraction layer, a first electrode layer, a light-emitting layer,a second electrode layer and an encapsulation layer that aresequentially disposed on the substrate, wherein the organiclight-emitting diode further comprises a second light extraction layer,and the second light extraction layer is disposed adjacent to theencapsulation layer; the light-emitting layer is an organiclight-emitting layer and the first electrode layer is an anode layer ora cathode layer and correspondingly the second electrode layer is acathode layer or an anode layer.
 2. The organic light-emitting diodeaccording to claim 1, further comprising: a hole injection layer and ahole transport layer that are sequentially disposed between the anodelayer and the light-emitting layer; and/or an electron injection layerand an electron transport layer that are sequentially disposed betweenthe cathode layer and the light-emitting layer.
 3. The organiclight-emitting diode according to claim 1, wherein the substrate is anarray substrate and the anode layer is electrically connected with aswitch element of the array substrate.
 4. The organic light-emittingdiode according to claim 1, wherein the first light extraction layer ismade of nano-glass powder.
 5. The organic light-emitting diode accordingto claim 4, wherein the nano-glass powder includes ZnO, BaO and B₂O₃. 6.The organic light-emitting diode according to claim 5, wherein in thenano-glass powder, a mass ratio of ZnO, BaO and B₂O₃ is 1 to 2:1 to 5:1to
 2. 7. The organic light-emitting diode according to claim 4, whereina thickness of the first light extraction layer is 10 nm to 50 nm. 8.The organic light-emitting diode according to claim 1, wherein thesecond light extraction layer is made of a resin material.
 9. Theorganic light-emitting diode according to claim 8, wherein the resinmaterial is a light-cured resin or a heat-cured resin.
 10. The organiclight-emitting diode according to claim 1, wherein a surface of thesecond light extraction layer has a regular texture structure.
 11. Amanufacturing method of the organic light-emitting diode, comprising:providing a substrate; and forming a first light extraction layer, afirst electrode layer, a light-emitting layer, a second electrode layerand an encapsulation layer sequentially on the substrate, wherein themethod further includes disposing a second light extraction layer, andthe second light extraction layer is disposed adjacent to theencapsulation layer; the light-emitting layer is an organiclight-emitting layer and the first electrode layer is an anode layer ora cathode layer and correspondingly the second electrode layer is acathode layer or an anode layer.
 12. The method according to claim 11,further comprising: forming a hole injection layer and a hole transportlayer between the anode layer and the light-emitting layer sequentially;and/or forming an electron injection layer and an electron transportlayer between the cathode layer and the light-emitting layersequentially.
 13. The method according to claim 11, wherein forming thefirst light extraction layer comprises: coating a light extraction layermaterial on the substrate; pre-baking to remove solvent of the coatedlight extraction layer material; sintering in nitrogen gas to remove theorganic material.
 14. The method according to claim 13, wherein thelight extraction layer material includes nano-glass powder.
 15. Themethod according to claim 14, wherein the nano-glass powder includesZnO, BaO and B₂O₃.
 16. The method according to claim 11, wherein formingthe second light extraction layer comprises: coating a resin material onthe encapsulation layer by a printing process; and solidifying the resinmaterial through a heating process or an UV light curing process. 17.The method according to claim 16, wherein the resin material is alight-cured resin or a heat-cured resin.
 18. The method according toclaim 11, further comprising: forming a regular texture structure on asurface of the second light extraction layer.
 19. The organiclight-emitting diode according to claim 2, wherein the substrate is anarray substrate and the anode layer is electrically connected with theswitch element of the array substrate.
 20. The organic light-emittingdiode according to claim 2, wherein the first light extraction layer ismade of a nano-glass powder.